Currently, clinicians can offer little hope to people addicted to psychostimulants - as many as 9 out of 10 will relapse within the first year of completing a rehabilitation program. Human studies of addiction model real world experience by inducing relapse with psychological stressors. Unfortunately, effective methods for inducing psychological stress in rodents are lacking at present, with most studies relying on physiological stressors. This need is addressed here with a Cognitive Stress (CoSt)-induced reinstatement model that uses non- invasive methods to induce cognitive stress (e.g. no need for physiologic stressors such as foot shock). The central hypothesis is that psychological stress will model the cognitive stress experienced by substance abusers after rehabilitation and reinstate drug seeking behavior in adult animals. In addition to being a means to elicit cognitive stress in adulthood, our use of early life stress reminders as one of the stressors has direct connections to addiction. Self-reports of childhood abuse and neglect are extremely high in addicts, up to 80- 90%. Consistent with this, animal models of early life stress reveal an increased vulnerability to drugs of abuse in adulthood. This project will determine the cognitive stressors that most effectively reinstate drug seeking behavior, as well as identify the brain regions that are activated by CoSt-induced reinstatement. The working hypothesis is that an acute psychological stressor or an olfactory reminder of early life stress will effectively reinstate drug seeking in ault rodents and recruit brain regions critical for emotional memory and reward- based strategies. The approach involves the simple union of common and widely used behavioral stressors (e.g. neonatal isolation) with reinstatement of drug seeking. In additional, through cellular imaging of activity in specific neuronal subtypes, the brain regions activated by CoSt-induced reinstatement will be identified. The contribution of the proposed research is simple, yet highly impactful - it s expected to yield the first animal model in which drug seeking behavior is reinstated by psychological stress. By mirroring the stress that substance abusers experience after rehabilitation, CoSt-induced reinstatement will provide a new platform with unprecedented clinical relevance for therapeutic discovery efforts. This model will be available to the entire fild, accelerating the missions of NIDA and NIAAA to treat substance and alcohol-related abuse and addiction. Further innovation of this approach lies in the integration and elevation of well-established behavior proto- cols to investigate relapse to drug seeking in an entirely new way; one that mirrors the post-rehabilitation struggle experienced by addicted individuals. Importantly, this approach has a high likelihood of success for the same reason - it involves the straightforward integration of well-established behavior protocols by a laboratory that has extensive experience with behavioral manipulations and addiction research. PUBLIC HEALTH RELEVANCE: By providing the first method to model relapse induced by psychological stress, the proposed project is anticipated to improve the clinical relevance of basic research efforts. This is expected to profoundly impact the field's ability to identify novel therapeutic targets for relapse prevention. Importantly, this invaluable tool will be available to ll researchers in the field, contributing significantly to the NIDA and NIAAA efforts towards developing effective treatments for substance abuse relapse.